1. Field of the Invention
The present invention relates to cervical orthoses, and more specifically to an orthosis for stabilizing the cervical spine employing maxillary and occipital fixation.
2. Description of Related Art
Heretofore, numerous orthotic devices have been developed whose purpose is to control, restrict, or stabilize cervical motion, or to fully immobilize the cervical spine. The known devices may be generally characterized as falling into one of two groups, a first group providing fully adequate, nearly complete immobilization or securing of the cervical spine, at the sacrifice of patient comfort, and a second group of devices providing relief from patient discomfort while sacrificing the adequate immobilizing or securing properties of the device.
Several types of available cervical orthoses are described in Sypert, G. W.; "External Spinal Orthosis", Neurosurgery; April 1987, 20(4): p. 642-9. The basic cervical collar discussed therein has a major disadvantage in that the collar does little to restrict cervical motion or to transfer weight off of the cervical spine. The "poster-type" orthosis, known by such names as the "Guilford orthosis" or the "S.O.M.I." (Sternwooccipital Mandibular Immobilized), has a major disadvantage in that this type of brace poorly controls upper cervical flexion, as well as rotational and lateral bending motion of the cervical spine. A further type of orthosis, termed a "cervicothoracic orthosis", described in Sypert allows up to 50% unrestricted lateral bending as well as permitting some amount of flexion and extension of the cervical spine.
The "halo" orthosis, described in Sybert as well as in other publications and patents, is currently believed to be the most secure means of controlling cervical motion in flexion, extension, lateral bending, and rotation. The halo orthosis device derives its name from the use in the orthosis of a halo or ring which is rigidly attached, by pins or bolts, into the skull of the patient. The ring or halo is held rigidly in place by a support mechanism comprising a vest or harness attached to the patient's upper body and a plurality of rigid upright posts connected to and extending between the vest and the halo.
Use of the halo orthosis carries very significant risks due to various complications which may arise from use. Potential complications, in addition to severe patient discomfort, include pin track infection, unsightly scarring, brain abcess, penetration of the skull, and subdural empyema.
Various braces and orthoses are also disclosed in U.S. Pat. Nos. 4,735,196; 4,383,523; 4,643,174; 4,477,041; and 3,724,452. Each of these devices shares one or more of the above-mentioned disadvantages. For example, U.S. Pat. No. 4,735,196 discloses a halo-type orthosis designed to increase patient comfort and increase stabilization of the cervical spine by altering the upper body support design from those known in the art. This device still requires the use of pins partially embedded in the skull as the head stabilizing attachment. Heretofore lacking in the cervical spine braces or orthoses previously known in the art is an orthosis which provides full or nearly full immobilization capabilities while eliminating the potential complications, risks and discomfort associated with the halo-type orthosis.
It is therefore an important object of the present invention to provide a cervical spine orthosis having substantially all of the positive attributes of halo-type orthosis, while substantially eliminating the negative attributes of such an orthosis.
It is a further object of the present invention to provide a cervical spine orthosis having a vest or upper body support member, a plurality of rigid uprights, and a maxillary bridge and occipital support pads attached to a metal band, the uprights being attached between the upper body support member and the metal band.
It is a further object of the present invention to provide a maxillary bridge component adapted to be attached to a surrounding band and rear support means also attached to the band, the bridge component and rear support means being readily adapted to be used in place of a skull-penetrating halo in a halo-type orthotic device.